Soap thickened hydraulic oil composition

ABSTRACT

An improved antileak hydraulic oil of the gel-thickened type comprises an effective amount of a lithium soap (e.g., 0.1-1% Li stearate) or an aluminum soap (e.g., 0.5-2% Al stearate), or mixtures of such soaps, and a base oil having a viscosity in the range of 70-3000 SUS at 100*F., said base oil comprising at least one hydro-refined naphthenic oil or a hydrocracked paraffinic oil having a viscosity in the range of 40-12,000 SUS at 100*F. The hydraulic oil can also contain an antirust agent (e.g., 0.02-2%) barium petroleum sulfonate, an antioxidant (e.g., an amine type) and an antiwear (e.g., 0.1-5% zinc dialkyl dithiophosphate).

United States Patent [191 Griffith, III et al.

[ 1 SOAP THICKENED HYDRAULIC OIL COMPOSITION [75] Inventors: John Q. Griffith, lIl; Edward s.

Williams, both of Claymont, Del.; William H. Reiland, J r., West Chester, Pa.

[73] Assignee: Sun Oil Company of Pennsylvania, Philadelphia, Pa.

[ Notice: The portion of the term of this patent subsequent to Sept. 26,

1989, has been disclaimed.

[22] Filed: Sept. 7, 1971 [211 Appl. No.: 178,479

Related US. Application Data [63] Continuation-impart of Ser. No. 34,899, May 5,

1970, Pat; NO. 3,694,363.

[52] US. Cl 252/72, 252/35, 252/41, 252/73, 252/74, 252/75, 252/76 [51] Int. Cl C09k 3/00 [58] Field of Search 252/72-76, 252/35, 41; 208/14, 18

[56] References Cited UNITED STATES PATENTS 2,528,348 10/1950 Denison et al 252/75 3,039,967 6/1962 Henry et a1. 252/75 3,156,652 11/1964 Fuehr 252/75 3,175,976 3/1965 Fuehr 252/75 3,203,896 8/1965 Latos et a1. 252/75 X 3,242,068 3/1966 .Paterson 208/18 X 1*June 11, 1974 OTHER. PUBLlCATlON S Georgi: Motor Oils and Engine Lubrication," (1950), Pub. by Reinhold Pub. Co., pp. 108, 153, 154.

' Primary Examiner-Leon D. Rosdol Assistant Examinerl-larris A. Pitlick Attorney, Agent, or FirmG. L. Church, Esq.; J. E. Hess, Esq.; B. A. Bisson, Esq.

[5 7] ABSTRACT An improved antileak hydraulic oil of the gelthickened type comprises an effective amount of a lithium soap (e.g., 0.1-1% Li stearate) or an aluminum soap (e.g., O.5-2% Al stearate), or mixtures of such soaps, and a base oil having a viscosity in the range of 703000 SUS at 100F., said base oil comprising at least one hydro-refined naphthenic oil or a Y hydrocracked paraffiuic oil having a viscosity in the range of 4012,000-SUS at 100F. The hydraulic oil can also contain an antirust agent (e.g., 0.022%) barium petroleum sulfonate, an antioxidant (e.g., an amine type) and an antiwear (e.g., O.l5% zinc dialkyl dithiophosphate).

18 Claims, No Drawings SOAP THICKENED HYDRAULIC OIL corvwosmon CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of our application Ser. No. 34,899, filed May 5, 1970, now U.S. Pat. No. 3,694,363 issued Sept. 26, 1972.

The following patents and applications, all assigned to The Sun Oil Company (as is the present application), are related to the disclosure of the present application in that they disclose methods of obtaining aromatic extracts or concentrates, distillate oils, hydrocracked oils and hydrorefined oils, which can be used to make the hydraulic oil composition of the present invention.

The disclosure of all of the following applications and patents is hereby incorporated in the present application:

U.S. Pat. No. 3,462,358 issued 8-19-69, U.S. Pat. No. 3,681,279 issued 8-1-72, U.S. Pat. No. 3,502,567 issued 3-24-70, Ser. No. 730,999 filed -22-68, U.S. Pat. No. 3,619,414 issued 11-9-71, Ser. Nos. 850,716 and 850,717 both filed 8-18-69 (both now abandoned), U.S. Pat. No. 3,654,127 issued 4-4-72, Ser. No. issued 8-1-72, Ser. No. 35,231 filed 5-6-70, Ser. No. 60,642 filed 8-2-70 (now abandoned), U.S. Pat. No. 3,715,302 issued 2-6-73, U.S. Pat. No. 3,732,154, issued 5-8-73, U.S. Pat. No. 3,663,427 issued 5-16-72, U.S. Pat. No. 3,666,657 issued 5-30-72, Ser. No. 140,398 filed 5-5-71 and U.S. Pat. No. 3,759,817 issued 9-18-73.

U.S. Pat. No. 3,383,312 to Walter J. Coppock is also pertinent since it describes a method of preparing a fluid soap thickened mineral oil lubricant composition, which method can be useful in practice of the present invention.

BACKGROUND OF THE INVENTION The industrial oil market is continuing to grow at a rapid pace. Accompanying this growth is the demand for better lubricant properties. Specific improvements are needed to cope with trends towards more severe operating conditions and better pollution control. In the response to these requirements, research has made important advances in upgrading antiwear and antileak properties. Wear-resistant oils can alleviate the equipment problems and failures caused by increased pressures and temperatures, shock loading, reduced tolerances, etc. Antileak oils can decrease the undesirable loss of lubricants. Not only do these latter oils reduce consumption, but they held curb the pollution of our natural waters. These problems are considered in greater detail in our patent U.S. Pat. No. 3,694,363, issued 9-26-72.

SUMMARY OF THE INVENTION An improved antileak hydraulic oil of the gelthickened type comprises an effective amount of a lithium soap (e.g., 0.1-1% Li stearate) or an aluminum soap (e.g., 0.52% Al stearate), or mixtures of such soaps, and a base oil having a viscosity in the range of 70-3000 SUS at 100F., said base oil comprising at least one hydrorefined naphthenic oil or a hydrocracked oil having a viscosity in the range of 40-1 2,000 SUS at 100F. The hydraulic oil can also contain one or more of the following: an antirust agent (e.g., 0.022% typically 0.2% barium petroleum sulfonate),

an antioxidant (e.g., 0.054% of anamine type), an antifoam (e.g., 0.051% of a silicone type) and an antiwear (e.g., 0.15%, typically 0.3-2%, zinc dialkyl dithiophopshate, such as zinc-isopropyl, decyldithiophosphate) or tricresylphosphate. For systems having seals comprising synthetic rubbers (e.g., Buna N, GRS, ABS) it is preferred that the aniline point of the base oil be in the range of 150l70F. For systems where the seals are of other rubbers or materials, a higher aniline point may be required (e.g., for the silicone rubbers an aniline point of about 200F. imparts the proper seal-swelling character to the hydraulic oil). In calculation of the aniline point of the base oil, one must consider the contribution of aromatic additives (e.g., those marketed as sea] swell agents) and the hydrocarbon diluent used in many commercial additives. The term base oil in the present application refers to the total hydrocarbons of the 40l2,000 SUS viscosity range which are present in the final hydraulic oil, it being understood that some of these hydrocarbons can be contributed via the usual commercial additives.

A preferred antioxidant is DBPC (ditertiarybutyl paracresol) or an amine type, used in combination with sufficient zinc dialkyl dithiophosphate to impart antiwear properties (e.g., 0.010-020% Zn).

The hydraulic oil can show good antiwear and antileak performance and good hydrolytic and oxidation stability in the ASTM D943 turbine oil stability test (TOST).

The base oils preferably contain less than ppm of basic nitrogen and can be those described in the previously cited applications of Mills et a1. and, more preferably, are blends of two or morehydrorefined naphthenic oils (e.g., a blend of a SUS at 100F. hydrorefined naphthenic oil and a 2500 SUS at 100F. hydrorefined naphthenic oil) or a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil.

In the hydraulic oil of the present invention, leakage reduction is achieved by designing into the lubricant the ability to maintain good rubber seal condition (e.g., by proper choice of aniline point of the base oil) and the ability to obstruct small leaks with retardant materials (e.g., Li or Al coaps or polymers). Plant trials have been conducted comparing the performance of the antileak hydraulic oils of the present invention to current, standard products. Lubricant loss was lowered as much as 88% by the leak resistant formulations. These antileak hydraulic oils of the present invention also have good overall properties and have performed well in many types of plant equipment.

FURTHER DESCRIPTION The hydrocarbon base oil can also contain a low nitrogen content paraffinic distillate or solvent raffinate oil, a hydrorefined parafiinic distillate or raffinate, a viscosityindex improver (e.g., high molecular weight polybutene or a polyacrylate or polymethylacrylate,

Paraffinic oils are those having a viscosity-gravity constant (VGC) in the range of 0.790 to 0.819 (preferably above 0.799).

Naphthenic oils have a VGC in the range of 0.820 to 0.899 and the preferred hydrorefined naphthenic oils have a VGC in the range of 0.840 to 0.899. Hydrorefined, relatively aromatic oils, having a VGC in the range of 0.900 to 0.920, can sometimes be used as a whole or partial substitute for the hydrorefined naphthenic lube. Aromatic oils (including hydrorefined or hydroaromaticized oils) having a VGC in the range of 0.921 to 1.050 and greater, can be useful in minor proportions (e.g., l20%) for adjusting the aniline point of the base oil, particularly when the base oil contains a high proportion of a high Vl hydrocracked paraffinic oil.

As an additional component, or as a partial or complete substitute for the hydrorefined naphthenic oils previously described, hydraulic oils of the gel or polymer thickened types can contain a wax-free, hydrogenated polyolefin oil (e.g., see Canadian Patent 842,290; US. Pat. No. 3,598,740) or ahigh viscosity index, hydrocracked oil or a mixture of such components. ln such blends an aromatic oil or concentrate rich in aromatic hydrocarbons (e.g., cycle oil) may have to be added to obtain the proper aniline point for seal swelling.

The preferred polyolefin oils are polymers or copolymers of C -C olefin which have a pour point no greater than 35F., and preferably below 50F. The hydrogenation can be from 50% to 100% of saturation and, preferably, is to a bromine number no greater than 10, more preferably less than 5. Preferred polyolefins include ethylene-propylene copolymer, polypropylene, polybutene (especially polyisobutylene), and poly(loctene).

The high Vl hydrocracked paraffmic oil component can be obtained by hydrocracking a high viscosity distillate or dewaxed distillate from a paraffinic crude (such as Lagomedio) and typically has a VI in the range of 90-l05 and contains in the range of 330% of aromatics by clay-gel analysis. The hydrocracked lubes are preferably stabilized (against UV light degradation and sludging) by extraction of the hydrocracked oil with aromatic selective solvents, such as furfural or phenol or by hydrorefining to reduce the 260 UVA at least 30% (preferably 40%).

The preferred stabilized hydrocracked oils (whether extracted or hydrorefined) are characterized by having a D-943 test life (to an increase in acid number of 2.0) which is at least 20% lower than the D-943 life of an unstabilized hydrocracked oil but which is at least 20% greater than the D943 life (with the usual amount of inhibitor) of an unhydrocracked solvent refined lube of the same viscosity.

One process for preparing a high Vl hydrocracked oil comprises fractionating the stock material (such as an atmospheric residuum from Lagomedio crude) into three fractions, boiling at (a) from 720855F., (b) 855-980F. and (c) the residuum or a fraction boiling at from 986-l070F., solvent extracting fraction (b) with a solvent having preferential solubility for aromatics such as furfural, recombining the three fractions, dewaxing to F. pour point or lower, and hydrocracking the combined fractions at from 720-800F. using a hydrogen partial pressure of from 2,000 to 3,000 psi., and a sulfided nickel-tungsten catalyst supported on Serial No. Filing Date lnventor(s) 780,24] 1 l-l9-68 Thompson et al. 875,502 1 l-l0-69 Thompson 64,656 8- 1 7-70 Kress The preferred amount of gelling agent to add to a given base oil can be determined from an experimentally obtained soap in oil curve. That is, various amounts of soap are added to base oil samples (which canalso include some or all of the other additives) and the viscosity of the soap-oil samples is determined. The results are plotted as a viscostiy versus concentration curve. In such a curve, a point will be found where the viscosity suddenly increases greatly. This will be the minimum concentration of soap which should be put into the oil for antileak protection. Generally, about 0.1% more soap than this minimum concentration should be put into the oil. The maximum amount of soap (or other gelling agent) will be where the solution lumps-up or becomes non-homogeneous.

The preferred soaps are lithium or aluminum stearate; however, any of the prior art lithium or aluminum soaps which have been used in petroleum lubricants can be useful in hydraulic oils of the present invention. Such soaps are shown, for example, in US. Pat. Nos. 2,489,300 and 3,383,312. For soap thickening useful lithium or aluminum soaps include soaps of fatty acids containing in the range of 12-22 carbon atoms, preferably an unsubstituted fatty acid. Stearates, palmitates, tallates, laurates, oleates and mixed soaps are among the useful soaps.

Polymer thickened oils can contain a small amount of a soap as a dispersant for the polymer or as a stabilizer (see US. Pat. No. 2,489,300).

To reduce equipment leakage, is important that elastomeric seals and gaskets maintain a slight positive swell and remain pliable. Shrinkage and hardening allow oil to bypass. Certain base oils can help to keep the seals working properly A good test for judging if a base stock will properly condition the most commonly used seals, i.e., Buna N and. Neoprene, is the aniline point (ASTM D61 1). This test measures the solubility temperature of aniline and the lubricant. The aniline point is, therefore, a measure of solvency of the lubricant. Data obtained for the percent swell for Buna N and Neoprene seals for a series of 250 SUS at l00F. oils having aniline points ranging from 150F. to 230F. show, that to obtain a small positive swell with the seals tested, the base oil should have an aniline point between 150F. and lF. Lubricants which are mostly paraffinic in structure have high aniline points and will shrink the rubber and make it hard. This permits the lubricant to leak. On the other hand, if the aniline point is below F., excessive swell often occurs and the seal may be cut and torn by the rubbing surface, thereby allowing lubricant to bypass. This correlation does not necessarily apply to lubricants which contain seal conditioning additives.

For other rubbers, such as the silicones, a different aniline point range may be required for proper swelling (e.g., for silicone rubbers an aniline point in the range of 195-2l5F. is preferred).

Note that such prior art as US. Pat.No. 2,408,983 (which at column 5 shows an aniline point of 178F.), U.S. Pat. No. 2,489,300 (which in examples) and 2 shows aniline points of 145F. and l3lF.) and US. Pat. No. 2,616,854 (which shows a range of l75l90F.) lead the art away from our preferred ranges of l50-l70F. and l952l5F.

Besides utilizing a base oil which properly conditions the rubber seals and gaskets, leakage can also be reduced by restricting small openings with leak retardant materials. The leak retardant must be carefully selected so that the properties of the lubricant are not harmed. There are two basic types of antileak additives presently being used. The first is the polymeric type' which includes material having molecular weights greater than several hundred thousand (e.g. polybutene). The second involves gelling agents (e.g., organic salts of polyvalent metals or soaps) which can have molecular weights of about three hundred.

it has been postulated that the polymeric materials develop a more rigid structure in areas of low shear rates, such as the threads of a leaky coupling. The viscosity, therefore, increases and flow is hindered from the high pressure zone.

Gelling agents are believed to perform in a different manner. That is, they build up, fibers or log jams in small openings, thereby barricading them and preventing fluid flow.

Both of these types of antileak additives shear down temporarily when subjected to pump, valve, etc. operations. Permanent shear loss is also experienced to a limited degree. Because thisdoes occur, the equipment is able to operate satisfactorily without clogging problems.

There are no known products which completely stop leakage. One reason for this is that the types of leak retardants which can be used are limited by other performance characteristics. The antileak component must be a material which will not cause plugging in filters as small as 5 microns or interfere with servovalve operation where clearances are extremely critical. Other properties of the lubricant itself, such as the oxidation stability, foam resistance, etc., must not be sacrificed.

In the following examples, as in the rest of this application, all percentages are by weight.

ILLUSTRATIVE EXAMPLES A The best way to evaluate new formulations is in the actual machinery in which leak problems are encountered. There is presently no standard way to measure antileak properties in the laboratory. A laboratory method has been devised, however, which appears to correlate with field experience. This test has been useful in measuring good versus bad antileak oils or improvements over a given reference oil. The reference oil can be, for example, a rust and oxidation (R&O) inhibited paraffinic hydraulic oil. This R&O reference contains all of the necessary additives to guarantee good lubricant performance but incorporates no leakretardants.

The apparatus in measured is a U-shaped combination of 54" [1'01] mp- 6 ples, union sleeves, and elbows. They are joined together by hand'tightening in a U-shape and then spot welded to hold in a fixed position. One end of the U is capped, the other end is connected to a pressure source. The proceedure utilizes a 300 cc oil sample. The system is pressurized to 30 psi. with nitrogen and allowed to stand for 1 hour. The oil which has dripped out at the end of this period is collected and weighed.

As with most screening tests, this method can only predict whether the oil is better than another. It cannot indicate the degree of improvement to be provided. Nothing but a large amount of field experience can supply this information.

EXAMPLEI Polymeric Type Antileak Hydraulic Oils The incorporation of proper polymers into hydraulic oilsare concentrations as high as 5% can provide leakage protection. As can be seen in Table l, a typical product containing a high molecular weight butene polymer also has good overall properties. The base oils, which are naphthenic in nature, have an aniline point of 152F. and generally provide good rubber seal conditioning. Water separation, foam resistance, rust protection are all acceptable. The oxidation stability, as

measured by the ASTM D-943 proceedure, is 1,250 hours. Leakage resistance, according to the laboratory test is approximately 41% less than that of a lqhydrau i I Two field trials were run with hydraulic oil. The results of these equipment evaluations are listed in Table II. in the first field trial listed, three broaches were run for a period of two months at each of three separate plant locations. The broaches were'first run with the R&O hydraulic oil to determine baseline data. The polymeric antileak oil was then added to these same machines and consumption characteristics measured. As can be seen, the three divisions reported improvements of 46%, 88% and 50%, respectively. The second trial listed in Table II was run on a total plant basis. All machines using R&O hydrauwhich leakage characteristics are lic oil were studied for consumption during a 6 month period. These same machines were'then charged with the polymeric antileak hydraulic oil for an equivalent 6 month period. After the one year trial, this plant measured a reduction in lubricant consumption of 28%. Table III lists 12 machines in the second plant trial which had the largest amount of leakage with the R&O type hydraulic oil. The machines covered a wide range of operations. In these pieces of equipment, the leakage reduction afforded by the polymeric antileak hydraulic oil was 39%, significantly more than the percentage reported for the total plant. Good leakage reduction is obtained with l-6% polybutene (typically 2%).

The polymeric antileak lubricant after the field trials had experienced only the normal amount of degradation. Filter and valve operations were completely satisfactory. The one final property which had changed more than that of the R&O hydraulic oil was viscosity. The polymer loss by sheardown caused a viscosity decrease of approximately 10%. This loss did not cause any performance problems.

A polymer thickened antileak oil with good perform ance in the D943 test comprises 2% of a polybutene additive, 0.6% DBPC, 0.7 zinc dialkyl dithiophosphate and the remainder a blend of hydrorefined naphnormalv the polymericantileak thenic oil and hydrocracked paraffinic oil, the blend having an aniline point of 200F. and a viscosity at 100F. of 300 SUS.

EXAMPLE ll Gel Type Antileak Hydraulic Oils gen, 0.2 Ll-lSV with a presulfided Ni-Mo-oxide catalyst. In addition to the base oil, the hydraulic oil contained 0.25% Li stearate, 0.17% of an amine typeantioxidant (Dupont Ortholeum), 10 ppm of a defoamer (Dow Corning Silicone), 0.2% of a neutral barium petroleum sulfonate antirust agent, and 0.7% Zn dialkyl dithiophosphate (Elco 1 14). The Zn dialkyl dithiophosphate imparts especially useful antiwear and antioxidant properties to the hydraulic fluid and has excellent hydrolytic stability. The alkyl group of this additive can vary considerably, depending on the manufacturer; howeven'all such presently commercially available Zn dialkyl dithiophosphateantiwear additives can be used in the fluids of the present invention.

g EXAMPLE lll An antileak hydraulic oil was compounded using the same blended (i.e., 100 SUS and 2400 SUS hydro'refined naphthenic oils) base oil as in Example II; however, the additives were different from those in Example II, namely, 0.7% ditertiarybutyl para cresol (DBPC), 0.05% alkyl (Cg-C1 substituted succinic acid (Lubrizol 850), 0.1% dioctyl dithio-thia-diazole (Amoco 150), 2 ppm silicone defoamer (1000 est at 100F., Dow Corning 200 fluid). This hydraulic oil-required about 1000'hours of ASTM D-943 testing to reach an acid number end point of 2.0 In contrast, a hydraulic fluid with the same additives but made from unhydrorefined naphthenic oil failed after 200 hours of D.-943 testing.

Addition of zinc dialkyl dithiophosphate to provide 0.015% Zn in the final compounded oil imparts good antiwear properties.

EXAMPLE 1V .zinc dialkyl dithiophosphate) and as the base oil a 200 SUS blend of a 100 SUS hydrocracked paraffinic lube and a 500 SUS hydrocracked paraffinic lube. Both oils showed better D-943 test performance than the corresponding oils containing hydrorefined or unhydrore fined base oils.

Specific gelling agents (e.g., Li or Al soaps) appear to be more efficient than the polymers in reducing leakage at concentrations up to 3%. The Al soaps are less hydrolytically stable than the Li soaps. Lubricants containing these materials are, however, also somewhat less stable to oxidation. The overall properties of the gel thickened hydraulic oil are good. A hydrogenated naphthenic type blended base oil with an aniline point of 160F., for example, can be used to provide seal swell. Oxidation stability, as measured by the ASTM D943 proceedure, is about 300hours less than the polymeric version but about 200% better than a comparable oil containing naphthenic acid-free naphthenic distillate instead of the hydrorefined oil. The leak resistance of the gel type oil made from the hydrorefined base stock is twice as good as measured in laboratory equipment.

Field trial data was obtained with the gel antileak hydraulic oil of this example. Three presses were tested, one a horizontal type, and the other two vertical. These presses were operated from 880 hours to 1,944 hours. Leakage reduction when compared to the R&O hydraulic oil was 55%, 85% and 60%, respectively. These values are higher than the reductions reported for the polymeric antileak hydraulic oil. Filter and valve performance were completely acceptable. After this trial the condition of the product was excellent. There was not significant viscosity or acid buildup. A viscosity loss of about 15% occurred due to the sheardown of the gel, but there was still enough of the leak retardant present to maintain good leakage reduction.

Actual equipment testing has shown that polymeric I antileak hydraulic oils can reduce losses by 23 to 88%.

The gel containing antileak hydraulic oils are more efficient with reductions of 55 to 85% in plant equipment.

EXAMPLE V An antileak hydraulic oil was compounded using the same amount of lithium stearate and the same base oil as in Example I. The addition of 5% of a 200 SUS Duo-Sol extracted paraffinic lube having ananiline point-of 226F. improved theD-943 performance of the hydraulic oil. Similar results were obtained with 5% of'a 152F. aniline point blend of 25% 100 SUS and 2500 SUS naphthenic acid-free naphthenic distillates or with 2%% of the paraffinic oil and 2% of the naphthenic oil blend.

A 200 SUS hydrocracked paraffinic lube can be used instead of the paraffinic lube in this example.

The attached Table VI lists the properties of a series of hydrocracked oils' (stabilized by solvent extraction) which are especially suitable components for blending with hydrogenated and/or unhydrogenated naphthenic. oils and/or an aromatic concentrate to provide a suit able base stock having an aniline point in the range of 150170F. For such blending, the following formula can be used to predict the aniline point (AP) of the blended base stock (AP Base):

AP Base (X) (AP Paraffinic Component) +(1-X) (AP Naphthenic Component) where X is the volume fraction of the paraffinic component and l-X is the volume fraction of the naphthenic component.

An especially useful blended paraffinic component is obtained by blending parts by volume of a 60 SUS at F. hydrocracked paraffinic oil with 10 parts by volume of the unhydrorefined paraffinic oil (obtained by Duo-Sol extraction of a paraffinic distillate).

Another paraffinic component, which can also be used as a textile process oil (due, in part, to its high unsulfonatable residue) is obtained by substitution of the hydrocracked paraffinic oil for the solvent refined oil. Similar paraffinic components of higher viscosity and ponent, satisfactory seal swelling can be obtained at higher aniline points (e.g., about 200F.).

An especially useful soap and polymer thickened oil, for lubrication of textile machinery, can be made by adding lithium stearate (or lithium palmitate, laurate, oleate, etc.) and high molecular weight polyisobutylene to ahydrogenated naphthenic oil having a viscosityin the range of 60-300 SUS at 100F. For example, sufficient lithium stearate (0.7%) and polyisobutylene (1.9% Paratac) to produce a MacMichael viscosity of about 25 was added to a 150 SUS (at 100F.) hydrorefined naphthenic lube (aniline point 162) to which there was also added 1.3% of 40% chlorinated paraffin 10 Dissolve 13 parts stearic acid in 450 parts of paraffinic bright stock (or other high viscosity lube) at 200 F.

Add vAgrashell Kolate, 3 parts, to thestearic acid iii oil, mix and stir (e.g., about 8 minutes).

Add the benzoic acid in oil to the stearic-acid-oil- Kolate, heat with stirring, to 400F. then cool, with stirring to 220F.

The concentrate is especially useful at levels which impart 0. l-l% Al complex soap to the final hydraulic oil composition.

Agrashell Kolate is a reactive oxoaluminum compound for making complex aluminum soaps and greases.

TABLE 1 Polymeric Type Antileak Hydraulic Oil Lubricant Properties (Chlorfin 40), to improve load carryability of the oil, ASTM gie 0.4 of ditertiarybutyl paracresol and 2 ppm of a silicone Test Method Oil on antifoam. This lithium soap thickened textile lubricant viscosil SUS/[F D216] 250 242 cannot be made with a paraff ni c base oil of the same 25 viscosity SUS/210$: D216 504 45.3 viscosity since the paraffinrc oil IS not sufficiently com- Viscosity, lndex D2270 102 34 patable with soap to permit attainment of the desired i i y. H Z D445 53.9 52.1 MacMichael viscosity. Unhydrorefined naphthenic oil 2328 335 55 33: 441 1 332 canot be used in this oil because it causes discoloration FR, D92 495 385 and damage to textiles. Pour-.R D97 0 -25 The soap thickened, antileak hydraulic oils described 'Y o D1500 ,Gravrty, API D287 3L2 21.2 herein can be used as a functional fluid in energy ad- TAN KOH/g D664 0.07 0.0 sorber devices, such as those which can reduce the Copper Strindass D130 1 1 body and bumper damage caused by automotive colli- 9i D611 230 152 sions (e.g., see Publications 710536, 710537 and ggggggff f; D1401 20 710540 of the Society of Automotive Engineers; mid Foam, Tendency/Stability D892 year meeting, Montreal, Quebec, Canada on June Sequence 1, ml 20/0 5/0 7-l l, 1971. In such a combination the base oil should gequeme have an aniline point of about 200F. when the seals are Rust z' D6658 Pa/SS iii: of silicone rubber. Oxidation Stability, hrm D943 1.300 1,250

An aluminum complex soap concentrate, which is a sistance useful in the present invention, can be made as follows ggibggfi; 2? (all parts are by weight):

Dissolve 0.7 parts benzoic acid in 500 parts of bright 1 v stock (or other high viscosity lube) at 220 F. ll {02.21118cnd point.

TABLE II g g Polymeric Type Antileak Hydraulic Oil Consum tion, Gallons in R1 n11, ea. Plag Igi al Data. Hydraulic Oil Hydraulic Oil l Plant Trial Per Broach per week* at Division A 5.7 3.1 46 Division B 23.1 2.7 as Division C. 10.0 5.0

2 Plant Trial Total plant usage" 3,13 l .667 2,242,766. 28 Per unit manufactured .98 .75 24 month duration TABLE III Most Critical Machines v Average Weekly Consumption, Gallons R&O Antileak Type Equipment Hydraulic Oil Hydraulic Oil Broach I08 57 Automated Drill line 4| 33 Mill l2 l9 Drill 2l7 155 10 Gear Cutter 140 N2 Drill l98 35 Lathe 2|7 I78 Broach 32 28 Gear Cutter I02 57 Grinder 28 6 Drill 23 l6 l5 Lathe 66 25 Total 1.184 72l '7. Reduction 39 TABLE IV Gel Type Antileak Hydraulic Oil Lubricant Properties R840 Antileak ASTM Hydraulic Hydraulic Test Method Oil Oil Viscosity, SUS/100F. D2l6l 250 258 Viscosity. SUS/2 l0F. D2l6l 50.4 45.5 Viscosity, Index D2270 I02 23 Viscosity, cs/l00F. D445 53.9 55.6 Viscosity. CS/Z l 0F. D445 7.4 5.9 Flash, COC. F. D92 440 350 Fire. COC. F. D92 495 390 Pour, F. D97 0 40 Color Dl500 2.0 2.5 Gravity. APl D287 3l.2 22.l TAN. mgKOH/g D664 0.07 0.0 COpper Strip, class Dl30 l l Aniline Point, F. Doll 230 I60 Dem ulsibility/l 30F. Dl|

Separation. min. 10 25 40 Foam. Tendency/Stability D892 Sequence l. ml 2.0/0 5/0 Sequency ll. ml 20/0 25/0 Sequence lll, ml 20/0 5/0 Rust. Syn Sea Water D6653 Pass Pass Oxidation Stability. hr' D943 L300 900 Leak Resistance Gms Leaked H0 20 Reduction; '1 82 (l)Tn 2.0 TAN end point.

TABLE V Reduction, '71.

Gel Type Antileak Hydraulic Oil Plant Trial Data Horizontal Press 12 H 150 gal I500 psi Ambient 880 hr -l00 gal/wk 35-40 gal/wk 55-60 Vertical 22' Press 200 gal 50 gal I000 psi. I500 psi l50F 7 gal/wk 85 TABLE VI Properties of Hydroeracked Oils Aniline Viscosity ASTM Gravity Wtfk Point (SUS. l00F.) Vl APl Aromatics F.

l03 34.2 12 i 220 200 107 33.3 I l 235 500 107 31.5 I3 250 All oils dewaxed to a ()F. pour point by Chilling in a solvent.

The invention claimed is:

l. A soap thickened antileak hydraulic oil comprising an effective amount for thickening ofa lithium soap of a fatty acid having l 2-22 carbon atoms or an aluminum soap of said acid, and a hydrocarbon base oil having a viscosity in the range of- 80-3000 SUS at 100F said base oil consisting essentially of a blend of at least one hydrorefined naphthenic oil and at least one hydrocracked paraffinic oil, each said oil having a viscosity in the range of 40l2,000 SUS at 100F.

2. Hydraulic oil according to claim 1 and wherein said hydrorefined naphthenic oil contains less than 80 ppm of basic nitrogen and has a viscosity-gravity constant in the range of 0.8400.899.

3. Hydraulic oil according to claim 1 and wherein said soap is lithium stearate.

4. Hydraulic oil according to claim 1 and containing in addition a zinc dialkyl dithiophosphate antiwear agent.

5. Hydraulic oil according to claim 4 and wherein said hydraulic oil contains in the range of 0. ll% lithium stearate, in the range of 0.02-2% neutral barium petroleum sulfonate and in the range of 0.1-5% zinc dialkyl dithiophosphate.

6. Hydraulic oil according to claim 3 and containing in the range of 0.32% zinc dialkyl dithiophosphate antiwear agent.

7. Hydraulic oil according to claim 1 and wherein said base oil has a viscosity at 100F. in the range of 150-350 SUS.

8. Hydraulic oil according to claim 7 and containing in the range of 0. ll% lithium stearate.

9. Hydraulic oil according to claim I wherein said base P s e? 9f? snsitet sa r 9n; hy r ed.

Vertical Press 300 gal I25F I400 hr gal/wk naphthenic oil and at least one hydrocracked paraffinic oil.

10. Hydraulic oil according to claim 1 wherein said base oil contains less than 80 ppm of basic nitrogen.

11. Hydraulic oil according to claim 1 wherein said base oil has an aniline point in the range of l50-170F.

12. Hydraulic oil according to claim 1 and having an aniline point in the range of l952l5F. said hydraulic oil being suitable for use in contact with a silicone rub- 16. A polymer thickened antileak hydraulic oil comprisinga polybutene having a molecular weight higher than several hundred thousand in amount efiective to thicken the oil and a base oil consisting essentially of a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil.

17. A soap thickened antileak hydraulic oil compris ing an effective amount, for thickening, of a lithium soap of a fatty acid having 12-22 carbon atoms or of an aluminum soap of said acid, and a hydrocarbon base oil having a viscosity in the range of 80-3000 SUS at 100F., said base oil consisting essentially of a hydrorefined naphthenic oil or a blend of two or more hydrorefined naphthenic oils having a viscosity in the range of 40l2,000 SUS at 100F., at least one said hydrorefined naphthenic oil containing less than 80 ppm of basic nitrogen and having a viscosity-gravity constant in the range of 0840-0899.

18. Hydraulic oil according to claim 17 wherein said base oil is a blend of at least two hydrorefined naphw 

2. Hydraulic oil according to claim 1 and wherein said hydrorefined naphthenic oil contains less than 80 ppm of basic nitrogen and has a viscosity-gravity constant in the range of 0.840-0.899.
 3. Hydraulic oil according to claim 1 and wherein said soap is lithium stearate.
 4. Hydraulic oil according to claim 1 and containing in addition a zinc dialkyl dithiophosphate antiwear agent.
 5. Hydraulic oil according to claim 4 and wherein said hydraulic oil contains in the range of 0.1-1% lithium stearate, in the range of 0.02-2% neutral barium petroleum Sulfonate and in the range of 0.1-5% zinc dialkyl dithiophosphate.
 6. Hydraulic oil according to claim 3 and containing in the range of 0.3-2% zinc dialkyl dithiophosphate antiwear agent.
 7. Hydraulic oil according to claim 1 and wherein said base oil has a viscosity at 100*F. in the range of 150-350 SUS.
 8. Hydraulic oil according to claim 7 and containing in the range of 0.1-1% lithium stearate.
 9. Hydraulic oil according to claim 1 wherein said base oil consists of a blend of at least one hydrorefined naphthenic oil and at least one hydrocracked paraffinic oil.
 10. Hydraulic oil according to claim 1 wherein said base oil contains less than 80 ppm of basic nitrogen.
 11. Hydraulic oil according to claim 1 wherein said base oil has an aniline point in the range of 150*-170*F.
 12. Hydraulic oil according to claim 1 and having an aniline point in the range of 195*-215*F. said hydraulic oil being suitable for use in contact with a silicone rubber.
 13. Hydraulic oil according to claim 1 and having an aniline point of about 200*F.
 14. Hydraulic oil according to claim 1 and wherein said soap is selected from stearates, palmitates, tallates, laurates, oleates and mixtures thereof.
 15. Hydraulic oil according to claim 1 wherein said oil contains in addition a member selected from low nitrogen content paraffinic distillate, low nitrogen content paraffinic solvent raffinate oil, hydrorefined paraffinic distillate, hydrorefined paraffinic raffinate, polycyclic aromatic concentrate, unhydrorefined naphthenic distillate, and naphthenic acid-free naphthenic distillate.
 16. A polymer thickened antileak hydraulic oil comprising a polybutene having a molecular weight higher than several hundred thousand in amount effective to thicken the oil and a base oil consisting essentially of a blend of hydrorefined naphthenic oil and hydrocracked paraffinic oil.
 17. A soap thickened antileak hydraulic oil comprising an effective amount, for thickening, of a lithium soap of a fatty acid having 12-22 carbon atoms or of an aluminum soap of said acid, and a hydrocarbon base oil having a viscosity in the range of 80-3000 SUS at 100*F., said base oil consisting essentially of a hydrorefined naphthenic oil or a blend of two or more hydrorefined naphthenic oils having a viscosity in the range of 40-12,000 SUS at 100*F., at least one said hydrorefined naphthenic oil containing less than 80 ppm of basic nitrogen and having a viscosity-gravity constant in the range of 0.840-0.899.
 18. Hydraulic oil according to claim 17 wherein said base oil is a blend of at least two hydrorefined naphthenic oils. 